https://orcid.org/0009-0006-3712-5490
Figures
Abstract
Background
Postpartum hemorrhage (PPH) is the leading preventable cause of maternal morbidity and mortality globally, occurring in 4–6% of Canadian deliveries with evidence suggesting higher rates among Asian individuals. We compared rates of PPH and severe PPH in Ontario, Canada, among Asian and White individuals, focusing on the intersectional relationships between race, language, and immigration status.
Methods
We performed a population-based cohort study in Ontario, Canada (2013–2021). PPH was identified by diagnosis codes used to indicate blood loss of ≥500 mL (vaginal delivery) or ≥1000 mL (cesarean delivery). Severe PPH was defined as PPH with an intervention to control bleeding. Rates were examined by maternal self-reported race, immigration category, duration in Canada, and language at immigration. Modified Poisson regression models were fit to determine the relationships between race, PPH and severe PPH. Models were adjusted for maternal sociodemographic, clinical and obstetric practice factors.
Results
The study included 637,311 deliveries (30.9% Asian, 69.1% White). PPH and severe PPH occurred in 5.5% and 6.8%, respectively, of primipara, and 3.8% and 4.3%, of multipara. Asian race was associated with marginally increased PPH rates among multipara after adjusting for confounding (adjusted rate ratio (aRR) 1.06, 95% CI 1.01–1.10). Asian and White individuals experienced similar rates of severe PPH in an adjusted model (aRR 1.00, 95% CI 0.91–1.09). Overall, immigrants experienced lower rates of PPH than non-immigrants (4.4% vs. 5.5%, p-value <0.01); however, differences were observed after layering primary language, with Southeast Asian language speakers having the highest rates (6.3% vs. 5.5%; aRR of 1.40 (95% CI 1.18–1.54) compared with White individuals.
Discussion
Variation in PPH and severe PPH risk was observed across racial, immigration, and language groups in Ontario, with modest differences overall but meaningful heterogeneity across subgroups. More granular consideration of immigration characteristics may improve understanding of maternal health inequities.
Citation: Hossein-Pour P, D’Souza R, Gayowsky A, Oltean I, Chin E, Mehrabadi A, et al. (2026) Asian-White racial disparities in postpartum hemorrhage and severe postpartum hemorrhage in Ontario, Canada: A population-based cohort study. PLoS One 21(3): e0344365. https://doi.org/10.1371/journal.pone.0344365
Editor: Ahmed Mohamed Maged, Kasr Alainy Medical School, Cairo University, EGYPT
Received: July 2, 2025; Accepted: February 19, 2026; Published: March 12, 2026
Copyright: © 2026 Hossein-Pour et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: The dataset used in this study is held securely in coded format at ICES. ICES is a prescribed entity under section 45 of Ontario’s Personal Health Information Protection Act. Section 45 authorizes ICES to collect personal health information, without consent, for the purpose of analysis of compiling statistical information with respect to the management of, evaluation or monitoring of, the allocation of resources to or planning for all or part of the health system. While legal restrictions and data sharing agreements prohibit ICES from making the dataset publicly available, access may be granted to those who meet pre-specified criteria for confidential access, available at www.ices.on.ca/DAS. Data access is available to external public sector researchers either through collaboration with an ICES scientist or directly, following project approval, via a secure online desktop infrastructure (see above link for details). The full dataset creation plan and underlying analytic code are available in the supplementary materials, understanding that the computer programs may rely upon coding templates or macros that are unique to ICES and are therefore either inaccessible or may require modification.
Funding: This received funding from: the Innovation Fund of the Alternative Funding Plan for the Academic Health Sciences Centres of Ontario (grant number: HAH-22-001) and the Canadian Institutes of Health Research (grant number: PJT-186018). The funding sources had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication. The analyses, conclusions, opinions and statements expressed herein are solely those of the authors and do not reflect those of the funding or data sources; no endorsement is intended or should be inferred.
Competing interests: The authors have declared that no competing interests exist.
Introduction
Postpartum hemorrhage (PPH) is the leading preventable cause of maternal morbidity and mortality globally [1]. In Canada, PPH occurs in 4–6% of all deliveries and increasing rates of PPH have been recently reported in Canada and several other countries [2,3]. Severe PPH, defined as PPH requiring blood transfusion, hysterectomy, or interventions to control bleeding, occurs in 4.3 per 1,000 deliveries in Canada and has a case fatality rate of 2.4 per 1,000 cases [4]. Long-term complications of PPH are not well understood, but a recent study using longitudinal data in Québec showed that experiencing severe PPH was associated with a nearly two-fold higher risk of mortality after 10 years compared with those without severe PPH [5]. In Ontario, hemorrhage remains the leading cause of pregnancy-related deaths, accounting for 27.2% of maternal deaths between 2002 and 2022 [6]. Identifying pregnant individuals at heightened risk of PPH is critical, as severe morbidity and mortality resulting from PPH can be avoided with appropriate mobilization of resources and hemorrhage preparedness [7]. Asian individuals represent the largest and fastest-growing minority group in Canada, comprising approximately 19% of the national population and 25% of Ontario’s population [8].
Several previous investigations have demonstrated an association between PPH and Asian maternal race [9–15]. In particular, a systematic review and meta-analysis of risk factors for PPH found that Asian race was a definitive risk factor for PPH with a 40% increased risk in Asian vs White individuals [16]. Notably, the data on racial disparities in PPH included in this review were all from the United States (US). While population-based analyses of Asian-White disparities in pregnancy outcomes in Canada have not assessed PPH, there have been reports of higher rates of pregnancy complications associated with PPH, namely, placental abnormalities, operative delivery, and severe perineal trauma among individuals with Asian race [17].
Due to the multiple forms of individual and structural discrimination that can contribute to an individual’s experience, there is an urgent need to account for intersectionality, a framework that explains how different types of discrimination, such as xenophobia and racism, overlap and intensify one another, when exploring health disparities [18,19]. For example, an individual’s mother tongue can shape how they are perceived in health care settings, regardless of their race or country of origin, due to linguistic/accent discrimination [20–25]. Immigration-related factors are particularly relevant in the Canadian context, as approximately 70% of Asian individuals are immigrants compared to 22% of White individuals in Canada [26]. Failure to account for immigration-related factors, such as immigrant status, primary language, and duration of residence in Canada, in comparisons between race groups can obscure the role of systemic racism and discrimination in shaping health outcomes, potentially masking the true health disparities faced by racial minorities in Canada. To that end, the primary aims of this study were to quantify the variation in PPH and severe PPH between Asian and White individuals and to explore the intersectional relationships between race and immigration-related factors: immigrant status, maternal primary language, and duration of residence in Canada.
Methods
Study population and data source
We conducted a population-based, retrospective cohort study of pregnant individuals with a live birth or stillbirth >20 weeks’ gestation in Ontario, Canada between April 1, 2013 and March 31, 2021. This study was facilitated through ICES, an independent, non-profit research institute whose legal status under Ontario’s health information privacy law allows it to collect and analyze health care and demographic data, without consent, for health system evaluation and improvement (https://www.ices.on.ca/). Data sets used for this study are valid and reliable sources for perinatal research and are described in S1 Table [27–35]. These datasets were linked using unique encoded identifiers and analyzed at ICES.
Exposure and outcome variables
Maternal race information (self-reported and recorded by health care providers as Asian, Black, White, or Other) was obtained from prenatal genetic screening records. Thus, the study population was restricted to the approximately 70% of birthing individuals in Ontario that accessed prenatal genetic screening.
We obtained information on immigration-related characteristics from the Immigration, Refugees and Citizenship Canada (IRCC) Permanent Residents database. Specifically, immigration admission category (economic, family, refugee, other), landing date, and primary language (mother tongue) of immigrants to Canada were collected [36]. Using publicly available sources including The World Factbook, primary language at time of immigration was mapped to a world region based on the country or region where each language is most spoken (S2 Table) [37]. This mapping was then used to report rates of PPH and severe PPH among immigrants who self-identified as Asian by world region of primary language in the following groups: West Asia, Central Asia, East Asia, Southeast Asia, and South Asia (S2 Table). Duration of residence in Canada was calculated as time from landing date to the index birth date among foreign-born individuals and as time from mother’s date of birth to date of index birth for those born in Canada.
PPH was identified by diagnosis codes noted by a health care provider used to indicate blood loss of ≥500 mL following vaginal delivery or ≥1000 mL following cesarean delivery, as defined by Society of Obstetricians and Gynaecologist of Canada guidelines [38]. Severe PPH was defined as PPH requiring blood transfusion or additional interventions to control bleeding (e.g., curettage, compression sutures, uterine or other pelvic artery ligation, or hysterectomy) and was identified using hospital diagnosis and procedure codes using an algorithm adopted by the Canadian Perinatal Surveillance System [5].
Statistical analysis
We created two models to compare the incidence of PPH and severe PPH among Asian and White individuals. Model 1 used the variable of self-reported maternal race for the exposure (i.e., Asian vs. White) and stratified results by parity (nulliparous and parous). In Model 2, the Asian group was disaggregated to distinguish 1) Asian individuals who were immigrants versus non-immigrants, and 2) among Asian immigrants, maternal primary language/language region (e.g., English, East Asian language, South Asian language). In Model 2, due to limited sample sizes within immigrant language groups, parity was included as a confounder rather than used for stratified analyses. Minimum detectable effect sizes were estimated for each group relative to the reference population (White individuals) based on 80% power and a 0.05 significance level (S3 Table).
The distribution of maternal characteristics was assessed by self-reported race, immigration status, and maternal primary language world region among Asian immigrants. Standardized differences for binary and median variables were computed to compare the White and Asian groups. Crude rates of PPH and severe PPH were reported by self-reported race, immigration category, and maternal primary language world region among Asian immigrants. Multivariable Poisson regression models were used to estimate unadjusted and adjusted total effects, presented as relative rates (aRRs) and 95% confidence intervals (CIs) of PPH and severe PPH. Predicted probabilities of PPH were calculated by duration of residence in Canada and maternal race and language world region.
Models adjusted for duration of residence in Canada (continuous), maternal race*duration of residence in Canada, age at delivery (< 20, 25–29, 30–34, 35–39, 40 + vs. 20–24), parity (primiparous vs multiparous; Model 2 only), plurality, pre-pregnancy body mass index (< 18.5 kg/m2, 25.0–29.9 kg/m2, ≥ 30 kg/m2 vs. 18.5–24.9 kg/m2), age and labour force quintile (previously dependency quintile; Q2, Q3, Q4, Q5 vs. Q1); maternal resources quintile (previously deprivation quintile; Q2, Q3, Q4, Q5 vs. Q1), households and dwellings quintile (previously instability quintile; Q2, Q3, Q4, Q5 vs. Q1), maternal immigration admission category (economic, family, resettled refugee and protected person, other vs. not an immigrant), geographic location (rural vs. urban), tobacco use in pregnancy, drug and substance exposure in pregnancy, type of conception (assisted, unknown vs. spontaneous), first trimester prenatal visit, pre-existing diabetes, gestational diabetes, pre-existing hypertension, pregnancy-induced hypertension, previous cesarean delivery, placenta previa, placenta accreta spectrum, placental abruption, labour induction, labour augmentation, episiotomy, fetal presentation (breech, transverse, unknown vs. cephalic), duration of second stage labour (60–119 minutes, 120–179 minutes, 180–239 minutes, 240 + minutes, no second stage vs. < 60 minutes), mode of delivery (forceps delivery, vacuum delivery, forceps and vacuum delivery, operative vaginal delivery (forceps/vacuum unknown), first stage cesarean delivery, second stage cesarean delivery, cesarean delivery without labour, cesarean delivery (missing/unknown stage) or perimortem cesarean delivery vs. spontaneous vaginal delivery), gestational age (preterm, post-term, vs. term), infant birth weight (<3000g, 4000-4499g, ≥ 4500g, missing vs. 3000-3999g),and infant head circumference at birth (<33 cm, 35–36 cm, ≥ 37 cm. vs. 33–34 cm). Confounders were selected based on prior literature and consultation with clinical experts [10].
Sensitivity analyses
Model 2, which reports rates of PPH by maternal primary language among immigrants, was restricted to individuals who self-identified as Asian so that it aligned with the population used in Model 1. However, many individuals who reported Asian languages as their primary languages, particularly from West and Central Asia, did not self-identify as Asian at prenatal screening and thus were not captured in Model 2. These individuals may have self-identified as White, Black, Other, or had missing information on race. To address this, we conducted a sensitivity analysis using the same Asian language data and categorizations without restricting to those who had self-identified as Asian to determine the effect of this restriction.
Additionally, we assessed the robustness of the results to unmeasured confounding using E-value methodology [39].
This study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline [40]. Ethics approval was obtained from the Hamilton Integrated Research Ethics Board (Project ID 14419). Data management and analysis were performed using SAS, version 9.4 (SAS Institute Inc). All tests used 2-tailed significance set at p < .05.
Results
A total of 637,311 deliveries from 2013–2021 were included where White individuals represented 69.1% of the population and Asian individuals 30.9% (Fig 1). Approximately 70% of Asian individuals in this study population were immigrants (Table 1). Among Asian immigrants, the language distribution was 52.0% from South Asia, 26.8% from East Asia, 19.0% from Southeast Asia, 1.4% from Central Asia, and 1.0% from West Asia.
Demographics
Asian individuals were less likely to be < 24 years old (7.0% compared with 14.3% among White) and more likely to live in urban areas (99.3% vs. 89.7%). Rates of body mass index (BMI) >30 kg/m2 were higher in White individuals compared with Asian (17.5% vs. 6.6%). Asian individuals had higher rates of gestational diabetes (13.3% vs. 5.5%), episiotomy (22.0% vs. 13.8%), as well as vacuum delivery (14.0% vs. 9.7%). Rates of obstetric trauma (including 3rd and 4th degree perineal lacerations, high vaginal and cervical lacerations, pelvic hematoma, injuries to the pelvic joints and ligaments, and other pelvic injuries) were higher among Asian individuals (8.9% vs. 6.1%; Table 1).
Demographics among Asian immigrants
Among Asian immigrants, individuals speaking East Asian languages had the lowest rates of pre-existing hypertension (1.6% vs. 3.3% in White, 2.6% in all Asian) and the highest rates of mediolateral episiotomy (15.4% vs. 7.5% in White and 12.1% in all Asian). Those speaking Southeast Asian languages had the highest rates of preeclampsia (5.1% vs. 4.0% in White and 3.0% in all Asian), placenta previa (1.6% vs. 0.6% in White and 0.9% in all Asian), and preterm birth (8.7% vs. 6.2% in White and 7.0% in all Asian; Table 1).
Rates of PPH and severe PPH
Among primiparous individuals, PPH occurred in 5.48% of patients who identified as Asian and 6.78% of patients who identified as White (Fig 2). Severe PPH rates were 0.63% in primiparous Asian patients and 0.68% among primiparous White patients. Multiparous and full cohort rates are reported in Fig 2.
Overall, immigrants had lower crude rates of PPH and severe PPH compared with non-immigrants (Supplementary Fig 1). There were no substantial differences observed between immigrant classifications for either PPH or severe PPH. However, it was seen that as duration of residence increased, rates of PPH declined among Asian immigrants speaking languages from South Asia and Southeast Asia (Supplementary Fig 2).
Among primiparous Asian immigrants, those speaking languages from Southeast Asia had the highest crude rates of both PPH and severe PPH (Fig 2); this population also had the highest rates of PPH and severe PPH in the multiparous group.
Association between race and PPH (Model 1).
Among primipara, Asian individuals had lower rates of PPH than White individuals in the unadjusted model (RR 0.81, 95% CI 0.78–0.83, p < 0.001) though this association disappeared after adjustment for relevant covariates (aRR 0.99, 95% CI 0.95–1.03). Among multiparous individuals, Asian patients had lower unadjusted rates of PPH compared with White patients (RR 0.88, 95% CI 0.85–0.92, p < 0.001); however, after adjustment, multiparous Asian patients had higher rates of PPH (aRR 1.06, 95% CI 1.01–1.10, p = 0.01).
In the unadjusted analysis, the rate of severe PPH was lower for Asian patients compared with White patients (RR 0.91, 95% CI 0.85–0.98, p = 0.02); after adjustment no association between race and severe PPH was observed (aRR 0.99, 95% CI 0.91–1.09).
Association between maternal primary language and PPH (Model 2).
Asian immigrants speaking Southeast Asian languages had higher relative rates of PPH compared with White individuals in both the unadjusted (RR 1.15, 95% CI 1.09–1.21, p < 0.001) and adjusted (aRR 1.41, 95% CI 1.28–1.54, p < 0.001) models. They also experienced the highest rates of severe PPH, with an unadjusted relative rate of 1.40 (95% CI 1.20–1.63, p < 0.001) and an adjusted relative rate of 1.63 (95% CI 1.34–2.00, p < 0.001).
Individuals speaking East Asian languages had higher adjusted rates of PPH (aRR 1.09, 95% CI 1.00–1.19, p = 0.04), while those who spoke South Asian languages had a lower adjusted relative rate of PPH compared with White individuals (aRR 0.83, 95% CI 0.77–0.90, p < 0.001; Fig 3).
Adjusted models included duration of residence in Canada, age at delivery, multiple gestation, pre-pregnancy body mass index, maternal resources quintile, maternal immigrant status, urban vs. rural residence, tobacco use in pregnancy, drug and substance exposure in pregnancy, type of conception, first trimester prenatal visit, pre-existing diabetes, gestational diabetes, pre-existing hypertension, pregnancy induced hypertension, previous cesarean delivery, labour induction, labour augmentation, fetal presentation, duration of second stage of labour, mode of delivery, and infant birthweight.
Sensitivity analysis
Assessing the distribution of primary language by self-reported race showed that 30.7% of immigrants with Central Asian primary languages identified as White and 59.7% with West Asian primary languages identified as White (S4 Table). In the main analysis limited to individuals who self-identified as Asian, rates of PPH and severe PPH were lower across all categories compared to the unrestricted sensitivity analysis (S5 Table). The most prominent difference was individuals speaking West Asian languages had a 16% higher rate of PPH in the unrestricted analysis compared with the Asian restricted analysis (S5 Table).
The E-values for key associations between maternal race and primary language world region and PPH in all the study strata are provided in S6 Table. E-values for the point estimate and upper 95% confidence bound for PPH among Asian immigrants who spoke Southeast Asian languages were 2.16 and 1.88, respectively, suggesting moderately strong unmeasured confounding would be required to fully explain the observed associations.
Discussion
This study measured the impact of maternal race and immigration-related factors on PPH and severe PPH among Asian or White individuals in Ontario, Canada and found that, overall, variation exists by race and immigration.
Adjusted analysis showed higher rates of PPH among multiparous Asian individuals compared to their White counterparts, but no significant differences in primiparous individuals or in severe PPH rates. Although White individuals had higher crude PPH and severe PPH rates, this disparity disappeared in adjusted models, possibly accounted for by confounding factors such as obesity, rurality, and infant birthweight. A similar Ontario-based study measuring the impact of maternal race on maternal morbidity found that compared with White race, Asian race was associated with increased risk of gestational diabetes, placental previa, preterm birth, emergency cesarean delivery, and obstetric anal sphincter injury; however, they did not report on PPH or severe PPH [17]. Their findings nonetheless lend support to the presence of racial disparities in obstetric outcomes in Ontario. Furthermore, because our models adjusted for these same maternal and perinatal factors, the higher rates of PPH observed among Asian individuals in our study are unlikely to be driven by the higher prevalence of these conditions.
Immigrants had lower rates of PPH and severe PPH in both Asian and White groups, a pattern sometimes attributed to the “Healthy Immigrant Effect”, whereby newcomers are thought to have better health than non-immigrant populations upon arrival [41]. This has been proposed to result from the self-selection of individuals who are younger and healthier, as well as immigration policies that favour those with fewer health risks [41]. However, immigrants are not a monolith; Southeast Asian language speakers (primarily languages from the Philippines) had the highest crude and adjusted rates of PPH and severe PPH in our study. This is aligned with previous studies showing higher rates of severe maternal morbidity among immigrants to Canada from the Philippines [42]. US studies similarly found that among all Asian groups studied, Filipina patients had highest rates of two contributors to PPH: pregnancy-induced hypertension, and cephalopelvic disproportion [43,44]. Adjustment for maternal age, BMI, and education did not account for the disparities in maternal morbidity in those studies or in ours. These findings highlight the need for further research on disparities among Southeast Asian populations [43,44]. Our finding of a marginally higher adjusted PPH rate among East Asian language–speaking immigrants contrasts with a large U.S. study that found no significant difference in transfusion rates between Chinese, Japanese, and Korean women and White women [15]. This discrepancy may be explained by differences in how East Asian subgroups are defined (language-based vs ethnicity-coded), differences in immigration histories between Canada and the United States, and variation in obstetric practices across health systems. The modest elevation observed in our cohort may reflect system-level factors rather than population differences in risk.
Conversely, South Asian language speakers had the lowest crude and adjusted PPH rates in this study. This contrasts with a United Kingdom (UK) study where South Asian individuals had higher adjusted severe PPH rates than White individuals [45]. This difference is potentially explained by historical differences in immigration practices that cause distributions of the duration of residence and immigrant status to differ in the South Asian populations of Canada and the UK [46,47]. Notably, the UK study included UK-born South Asians, while our study only examined immigrants speaking South Asian languages.
Our findings suggest that the relationship between maternal race, immigration-related factors, and the risk of postpartum hemorrhage is nuanced and cannot be adequately understood through research relying on aggregated racial categories alone. Primary language likely serves as a proxy for several underlying social and structural factors, including cultural background, ethnic identity, and experiences within the healthcare system. Although language and ethnicity may be correlated, they are not interchangeable. In Ontario, the absence of detailed, self-identified race or ethnicity data in administrative health datasets limits our ability to distinguish whether the observed differences reflect ethnic inequities, experiences of systemic or institutional racism, differences in communication and care experiences related to language or accent, or other unmeasured factors. Nevertheless, the variation in PPH rates by maternal primary language among Asian immigrants, particularly the elevated rates observed among those speaking Southeast Asian languages, suggests that health system factors such as differential access to care, communication barriers, or health system bias may contribute to these disparities. A genetic or biological explanation for these differences is not supported by current evidence [48,49]. The concept of distinct genetic risk by racial group has been widely refuted, as genetic variation is far greater within groups than between them, and population categories such as “East Asian” or “Southeast Asian” do not map onto meaningful biological boundaries.
Our findings also highlight that immigrant populations are not homogenous, and that duration of residence may further shape risk. Future research should focus on disaggregating Asian populations more consistently, incorporating immigration history and language and exploring potential mechanisms underlying subgroup disparities.
Limitations
Our population was limited to the ~ 70% of Ontario pregnancies who accessed prenatal genetic screening [50], a group more likely to be urban, high-income, and under obstetric care [51]. While race was self-reported, our use of primary language has not been validated and should be interpreted cautiously. However, a benefit of this method is that the impact of immigration and primary language could be considered primarily, alongside the more commonly studied race/ethnicity. While mother tongue can be an important proxy, it does not necessarily indicate that an individual has experienced linguistic discrimination. As such, this study was intended as an exploratory examination to begin unpacking these complex dynamics and to inform future, more targeted research. We lacked data on individual income and deprivation measures and approximated these using neighborhood-level indicators. We also lacked information on several variables known to influence rates of PPH including coagulopathy, uterine fibroids, prior PPH, history of APH, anemia, and infection/chorioamnionitis. Additionally, because objective measures of blood loss are not available in the included administrative datasets, some misclassification of PPH is possible. However, our inclusion of severe PPH provides a more objective outcome that is less vulnerable to measurement error than estimated blood loss alone, even acknowledging the limitations of current blood-loss quantification methods [52]. Lastly, statistical power constraints prevented adjusted models for severe PPH by parity or maternal language world regions.
Conclusion
This study highlights disparities in postpartum hemorrhage and severe postpartum hemorrhage rates across racial, immigration, and language groups in Ontario, Canada. Across most comparisons, differences in risk were limited in magnitude, although heterogeneity was observed across subgroups. The findings underscore the importance of considering nuanced factors such as primary language and immigration patterns in maternal health research. The higher adjusted risk of postpartum hemorrhage among Southeast Asian language speakers specifically warrants further investigation, recognizing that these associations may be influenced by factors not captured in administrative data. Future research addressing limitations in socioeconomic and immigration data, as well as subgroup analyses, are needed to clarify these patterns and inform efforts to improve equity in maternal health.
Supporting information
S1 Table. Descriptions of data sources linked for analysis.
https://doi.org/10.1371/journal.pone.0344365.s001
(DOCX)
S2 Table. Maternal mother tongue language mapping to world region.
https://doi.org/10.1371/journal.pone.0344365.s002
(DOCX)
S3 Table. Calculated minimum detectable effect sizes for each population group compared with White individuals.
https://doi.org/10.1371/journal.pone.0344365.s003
(DOCX)
S4 Table. Distribution of mother tongue world regions and self-reported race.
https://doi.org/10.1371/journal.pone.0344365.s004
(DOCX)
S5 Table. Crude rates (95% confidence intervals) of PPH and severe PPH by maternal mother tongue world region, unrestricted by Asian self-reported race, Ontario, Canada, 2013–2021.
https://doi.org/10.1371/journal.pone.0344365.s005
(DOCX)
S6 Table. E-values expressing the required rate ratio (RR) for any unmeasured confounder to overcome the observed association of maternal race and mother tongue world region and PPH (postpartum hemorrhage) in this study.
https://doi.org/10.1371/journal.pone.0344365.s006
(DOCX)
S1 Fig. Crude rates of (A) PPH and (B) severe PPH by maternal race/ethnicity and maternal immigrant/refugee status.
https://doi.org/10.1371/journal.pone.0344365.s007
(TIF)
S2 Fig. Predicted probabilities of PPH by duration of residence and race.
https://doi.org/10.1371/journal.pone.0344365.s008
(JPG)
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